Not schoolwork — the questions that resisted Erdős, Hilbert, and everyone since. The club keeps three shelves: what is still open, what AI recently settled, and what took humanity centuries.
Tagged graph-labellings — 2 entries. Clear
Weight edges 1-2-3 so neighbouring vertex-sums differ. Always possible, with no isolated edges the only obstruction? Open since 2004.
Every connected graph except K2 has an edge-labelling with all vertex-sums distinct. Open since 1990; verified for paths, wheels, complete and dense graphs.
